The method of slush moulding plastisol or PVC powder or other materials is generally known and is described in the literature, of which the following examples can be cited:
1) "PLAST"--September 1979 pp 175-177. PA0 2) "MODERN PLASTIC ENCYCLOPEDIA" 1977-1978 pp 340 onwards. PA0 3) BALL W., Ziebart W., Woite B. (BMW) Mannheim VDI conference "New Requirement for Car Interior Trim" pp 1-18. PA0 4) Pabst H. G., Shaper S., Schmidt H., Terveen A. (AUDI) Mannheim VDI Conference 1987--"Development and large-scale sue of dashboards produced by Slush Moulding PVC". PA0 5) Khue N. N., Kunpers-Martz M., Dankmeier O. (EVC) "Development of optimum powder-blend for slush moulding" IVth International Conference PVC '90--Apr. 24-26, 1990, Brighton U.K., pp 31/1-31/14. FR-A-1,439,028 (Rhone Poulenc), CH-A-293,508 (J. Croning), FR-A-1,075,378 (Telegraph Construction), FR-A-1,381,850 (Gosudarstvenny), GB-A-905,546 (Plastomatic) U.S. Pat. No. 2,736,925 (J. S. Heisler), FR-A-1,131,153 (National Research), GB-A-1,337,962 (Aquitaine Total), GB-A-1,056,109 (Celanese), U.S. Pat. No. 3,039,146 (T. Hengel), U.S. Pat. No. 2,915,788 (T. Hengel), GB-A-865,608 (T. Hengel), FA-A-916,055 (ICI), GB-A-1,025,493 (M. F. Smith), FA-A-1,560,675 (Goodyear Tire), DE-A-1,554,967 (Vaessen-Schemaker), IT-A-22197 A/80 (ILPEA), DE-A-3,417,727 (YMOS).
All these patents or articles describe a substantially similar process, briefly consisting of filling a preheated metal mould with polymer liquid or powder, removing the excess liquid or solid and then heating the mould to complete gelling or fusion of the material which has adhered to it. The mould is then cooled and the final moulding extracted.
In the sector involving such articles a problem has recently appeared when trying to obtain a finished product, such as simulated leather for trimming an automobile dashboard, having two or more sharply divided colors in the exposed part of the moulding.